Process of making conduits



Oct. '8, 1935. c. J. KATZE-MILLER 2,016,447

I PRCESS 0F MAKING' CONDUITS Filed Jan. 14, 1933 Patented Oct. 8, 1935PATENT OFFICE 2,016,447 v rnoonss oF MAKING coNourrs Carlton J.Katze-Miller, Milwaukee, Wis., assgnor to Line Material Company, SouthMilwaukee, Wis., a corporation of Delaware Application January 14, 1933,Serial No. 65h70@ i Claims.

This invention relates to waterproof fibrous material and to the processof making the same, and is particularly directed to the manufacture ofconduits, pipes, ber board, wall board and various insulating materials.

In the manufacture of articles such as electrical conduits from fibrousmaterials as wood pulp, such, for instance, as that obtained from paperstock, it is the customary practice to disintegrate the stock by the useof a beater and conduct the web from a web forming machine to a rotarymandrel where it is wound into a tube of the desired thickness, themandrel being subsequently withdrawn and the tube dried. The stock is ofsuch a character and contains such an amount of water that the bers feltor mat to produce a substantially homogeneous fibrous tube. The tubesthus formed are dried and suhsequently impregnated with a waterproofingagent.

.These conduits formed from wood pulp have a certain amount of strengthand a certain life even when used in underground work, such as housingelectric wires, cables, etc., but they are expensive asthe cost of thewood pulp, whether from. paper stock or not, is a fairly large item.There is a decided need for a conduit which is materially cheaper, whichhas a long life, and which is very strong.,

This invention is designed to provide a brous product, such as aconduit, for instance, and

a method of making the same, which obviatesk the' disadvantageshereinbefore enumerated and which provides a fibrous conduit which isveryy much stronger than one formed of wood pulp,

which has a longer life, and which is considerably cheaper than theheretofore known type of wood pulp conduits.

lt has been found that leather ber can be used to greatly cheapen theprocess as the waste leather scrap from the leather` industry, thetannerles, shavings and scraps fromshoe factories, or other factoriesfor producing leather or leather articles, is usually discarded,frequently the factories paying to have it hauled away. This leatherscrap can, therefore, be obtained for almost nothing and in greatabundance.

This invention contemplates the use of leather ber, either alone, ormixed with wood fiber in the production of conduits and other brousproducts.

In practicing this invention it is advisable to rst thoroughly wash theleather scrap with water, preferablyslightly warmed, to remove the saltsthat the leather carries from the tanning. Thereafter the Washed leatherscrap is put into a beater, such as used in paper manufacturing, and, ifwood pulp is used, paper stock or other source of wood pulp is added tothe beater..

In one mode of carrying out the invention, the stock of leather and woodpulp is beaten with water. The beating continues until the fibrous massconforms to the standard sheet test. The fibrous mass then goes throughthe conventional 10 forming machines, such as conduit forming machines,in the usual maner.

Thereafter the conduit or other article is thoroughly dried, preferablythe drying starting at a moderate temperature and the temperature beinggradually increased.

After drying the conduit or other article it is impregnated with awaterproofing agent. Various impregnating compounds may be used, and,without limiting the invention thereto, a few may be mentioned,vim-asphalt, pitch, wax, lignin (which is found in the waste sulphiteliquors from paper making), casein, rosin, or paramn. The material whenimpregnated with casein may have the casein subsequently hardended bytne use of formaldehyde or other hard.-1 ening material." Theimpregnating preferably is conducted under pressure.

With certain impregnating material, such as asphalt, pitch, etc., it ispreferable to immediately 3@ spray the conduit or article afterimpregnating to cause it to become chilled suddenly to preventdistortion while it is hot.

In another mode of carrying out this invention leather ber alone may beemployed. 1mpregnation is vastly more diflicult, however, Where leatherfiber alone is used. It has been found that the addition of even a smallamount of wood ber greatly facilitates impregnation.

This invention, therefore, contemplates the use w of leather fiber inthe formation of conduits or other articles, with or without the use ofwood fiber, and if wood iiher is used, with the percentage of wood :berrunning all the way from 4@ a small percent with reference to theleather ber to a large percent.

The accompanying drawing shows a ni'shed conduit.

I have found that a leather ber product 5o shrinks very much on drying,whereas a wood fiber product has relatively little shrinkage during thedrying. Further, a wood ber product is easily impregnated with awaterproofing agent, whereas` a wholly leather ber product is dinicultlyimpregnated with a waterproong agent.

From numerous experiments I have found that there are practically novoids formed in a wholly leather ber product, and that there arenumerous voids formed in a wholly wood ber product.

It ,is, therefore, clear .that the relative proportion of wood ber toleather ber, varying al1 the -w'ay from zero to the desiredamount, willbe determined by the particular use for which the `article is designed.Excellent results have beenobtained for Wholly leather fiber productswhere the impregnation is not of paramount importance. However, Whereimpregnation forms a very importantfeature in the product, a mixture ofwood ber with leather ber produces the best results. The wood ber indrying produces the voids hereinbefore mentioned and allows theimpregnation to proceed with relative ease and with thoroughness.

I have given the brief summary of numerous experiments which I haveconducted not with a view to limiting the invention but with a view ofsetting forth what I believe to be the principles underlying mydiscoveries.

In still another mode of carrying out this invention, water need not beused in the beater but instead creosote with a suitable solvent may beemployed, or the product may be dipped in creosote to assist inwaterproofing the fibers. If the creosote is used in the beater, it hasbeen found that the bers will not pick up the same amount of water aswhere water was the liquid employed in the beater. Consequently there isless shrinking when creosote with a suitable solvent or diluent is usedin the beater.

It has been found that the strength of the conduit or other articlewhere leather liber is used, either mixed with wood ber or used alone,is many times greater than that of a wood fiber tubing.

Another feature of the resulting product is that it picks up lessmoisture, is considerably tougher, and has an increased life,particularly when used in underground work. l

Of paramount importance is the fact that the waste .leather is very muchcheaper than the wood pulp, Whether obtained from paper stock or fromother stock. Heretofore this leather scrap has been merely dumped orthrown away and may, therefore, be obtained with a minimum of expense,sometimes, in fact, without cost.

This invention, therefore, supplies a long felt want in providing a verycheap fibrous conduit or article and a. method which may be readilyfollowed in the production of such article.

Although this invention has been described in 5 considerable detail, itis to be understood that such description is intended as illustrativerather than limiting, as the invention may be variously embodied and isto be interpreted as claimed.

I claim:

1. The process of making a conduit which comprises disintegratingleather scrap into leather fibers, washing the same, solely withsubstantially pure water and mixing wood fibers therewith, shaping themixture of fibers into a conduit, drying the shaped conduit to formvoids adjacent the wood bers, iilling the voids with a hot waterproongmaterial, and subsequently suddenly chilling the impregnated conduit toprevent deformation of the impregnated conduit while it is hot.

2. The process of making a conduit which comprises washing leather scrapsolely with substantially pure water to remove the salts from tanning,disintegrating the scrap leather into leather fibers and mixing woodfibers therewith, shaping the mixture of fibers into a conduit, dryingthe shaped conduit, and impregnating the shaped conduit with awaterproofing material.

3."Ihe process of making a. conduit which comprises washing leatherscrap thoroughly with Warm water, said Water being substantially pureand free from any added ingredients, to remove tanning salts and otherimpurities, disintegrating the leather into fibers, mixing wood fiberstherewith, while wet, shaping the resulting wet mixture of fibers into aconduit, drying the shaped conduit and impregnating the dried conduitwith a suitable waterproong material.

4. The process of making a conduit which A comprises washing leatherscrap thoroughly with warm water, said water being substantially pureand free from any added ingredients to remove tanning salts and otherimpurities, disintegrating the leather into fibers, Amixing wood fiberstherewith, while wet, shaping the resulting wet mixture of bers into aconduit, drying the shaped conduit and impregnating the shaped conduitwith a material containing casein and hardening the same with analdehyde. 5

CARLTON J. KATZE-MILLER. .d

